Thermostatic carburetor control



March 13, 192 1,662,778

, I H. F. HUDSON v THERMOSTAI'IC CARBURETOR CONTROL Filed March 50,. 1925 "Harm-a farmer fludszm.

Patented Mar. 13, 1928.

UNITED STATES 1,662,778 PATENT OFFICE.

HAVARlD FARMER HUDSON, '01 WICHITA, KANSAS.

THERMOSTATIC GARIBURETOR CONTROL.

Application filed March 80, 1925. Serial No. 19,326.

This invention relates to iin 'irovements in automatic temperature controlled adjusters for carburetors.

It is well understood by all automobile a drivers that the carburetor should be adjusted differently whefi it is cold than when it is hot. When the engine starts and before the parts get warmed" up, the carburetor should be setso as to'supply a rich mixture which up can be changed to a lean mixture when the parts have become warmed up. The usual way is to adjust the carburetor to a. position intermediate that required for starting and that which produces the most economical results after the engine gets hot. This, it is evident, is not a very satisfactory solution for the reason. that this adjustment of the carburetor does not produce satisfactory operation when the engine is cold and it fails to give the best results after the engine has warmed up.

It is evident that the ideal arrangement would be one in which the mixture could be made very rich for an instant during the starting of the engine, this period to correspend with the choking effect now invari,

ably resorted to in starting. As soon as the engine has started the carburetor adjustment should be changed so as to prevent flooding of the engine, but so that the mix ture is still rich. As soon as the engine begins to warm up, the carburetor adjustment should be changed slowly until the point is reached where the most satisfactory :15 results are obtained under the average running conditions of the engine. It is evident that it will take an engine longer to warm up on a cold day than on a hot day and the adjusting mechanism should therefore be so constructed that the adjustments will be made at a slower rate on a cold day than on a warm day.

It is the object of duce a mechanism of simple construction that will adjust the carburetor. in the manner pointed out above.

It is a further object to so construct my device that it can be conveniently operated and even made automatic to this extent that no the same pressure that is applied to the starter button will set the automatic ad- 7 juster.

The above and other objects that will be-.

come apparent as the description proceeds .35 are attained by means of a construction and arrangement of parts which I will now prothis invention to pro-' ceed to describe in detail, reference for this drawing in which the preferred embodiment of my invention is shown and in which Fig. 1 is a side elevation, with a part broken away, of a carburetor of well known make with my adjusting device in place thereon.

Fig. 2 is a viewtaken along line 2-2,

Fig. 3 is a section taken on line 33, Fig. 2.

Fig. 4 is view showing the automatic means provided for setting my adjuster simultaneously with the closing of the starter switch, and r Fig. 5 is a view of a portion of the mechanism shown in Fig. 4; this view being taken gooking in the direction of the arrow 5 in In the drawing numeral 1 designates the .exhaust manifold of an internal combustion engine and 2 the instrument board. The carburetor to which my invention has been applied is of well known construction and .7 will therefore not be described to any reater extent than that required to proper y explain the present invention.

The part of the carburetor designated by the numeral 3 I designates the float chamber into which the gasoline enters and 4 designates the metering pin whose position within the opening 5 determines the richness of the fuel mixture.

purpose of varying the effective cross. section of the opening 5. A lever 8 is clamped onto the end of the shaft 7 by means of the split hub 9. This lever comprises a portion of the dash control of the carburetor. An arm 10 projects downwardly at right angles from the lever 8. To the lower end of. the arm -10 I connect a chain 11 whose other end is connected tothis lower end of the wire 12'that passes through the tube 13 and connects with the button 14 on the instrument board. A spring 15 has its upper end connected to a bolt 16, that passes through one end of the bracket 17, and its lower end connected to the lever 8 'bymeans of a chain 18. The spring 15 exerts aforce which tends to rotate the lever 8 and shaft 7 in a. clockwise direction thereby tending to move the metering pin 4 upwardly so as to restrict the area through which the liquidv fuel must pass. The extent to which the shaft 7 can be rotated in a clockwise directionis determined by the position of the screw 19 whose lower end serves as a stop for the shoulder 20. The screw 19 is adjusted so that when the shoulder 20 is in contact therewith, the mixture is as lean as it can be satisfactorily employed under ordinary running conditions. The nut 21 is so adjusted that'the spring 15 will cease exerting any force on the lever 8 some time before the shoulder 20 engages the screw 19. For the purpose of moving the lever 8 after the spring 15 has ceased to function, I attach a small weight 23 to the right hand endof the lever 8 in the manner shown in Fig. 1. This weight eX- erts a force tending to rotate the shaft 7 clockwise and this force is exerted as a series of hammer blows caused by the vibrations to which the parts are subjected. The importance of this weight in the operation of my device will become apparent as the description procee'ds. A second spring which is designated by numeral 24 has its upper end connected to the outer end of the bracket 17 in the same manner as spring 15. The lower end of spring 24 is connected to the left hand end (Fig. 1) of lever 8 by means of a chain 25. The spring 24 is stronger than the spring 15 and the chain by means of which it is connected to the lever is so long that the spring is not put under tension until after the lever 8 has been rotated counter-clockwise to a considerable extent.

It Is now apparent that if the driver pulls the wire 12, he will rotate the shaft 7 counter clockwise first against the resistance of the weight 23, then against the combined resistance of weight 23 and spring 15 and finally against the combined resistance of the weight- 23 and springs 15 and 24. As soon as the force applied to the wire 12 is removed, the springs and the weight will cooperate to return the lever 8 to normal position, unless some means is provided to prevent this. I will now describe the means that I have provided to prevent the lever from returning to normal position .until the engine gets warmed up.

A cylindrical casing 26 is secured to the carburetor by suitable means such as the bracket 27. Within the casing 26 and spaced from the latter is a similar box or casing 28.

that contains a wax 29 or other composition that becomes hard at ordinary temperatures,- but which softens when heated. As examples of such a wax I will mention bees wax and sealing wax. I may also use some hydrocarbon product such as asphaltum or some easily fusible alloy such as Woods metal. In fact any material that solidifies at ordinary temperature and becomes liquid at such temperature as may readily be obtained by the heating means to be employed. A pipe 30'extends from the casing 26 to the exhaust manifold 1. This pipe is provided with a stop cock 31 by means of which the amount of exhaust gases that are permitted to flow through it may be controlled. A. similar pipe 32 extends downwardly and terminates at some suitable point underneath the car. Within the casing 28 is a similar but smaller casing 33, whose sides are perforated by a large number of openings 34 and which is secured to the end of the shaft 35. The wax 29 fills, or partly fills, the casing 28 and the interior of the casing 33. When the wax is hard, the shaft 35 and attached casing 33 cannot be rotated but when the wax is soft the shaft can .be turned. The hot exhaust gases from the manifold 1 produce sufiicient heat to melt the wax or other fusible material 29. Instead of a cylindrical.

casing 33, such as shown, any other suitable member may-be substituted as the function of this element is merely to engage the wax to prevent or retard the movement of the shaft 35. A pipe 86 connects with the interior of the casing 28 so as to permit the wax to be introduced. The outer end of this pipe is closed by a vented cap 37. The other end of the shaft 35 is journalled in a bearin in the bracket 17 and carries a ratchet whee 38. A lever 39 is pivoted at one end to the shaft 35 and carries a spring pressed pawl 40 that engages the teeth on the ratchet wheel.

\Vhen thelever 39 is moved in a counter clockwise direction, the pawl 40 will ride over the teeth of the ratchet wheel. but will whose lower end is connected, by means of a pin 42, with one of the holes 43 in lever 8. The upper end of link 41 is flattened as indicated by numeral 44 and to this flattened end a-slotted bar 45 is connected-by means of a bolt 46. A pin 47 extends through a hole in the end of the lever 39 and through the slot in the bar e5. An adjustable clamp 48 can be moved to various parts of the slot in member 45 and the position of this member determines the amount of lost motion between link 41 and the lever 39. Let us now assume that the parts are assembled as described and that the wax 29 is hard and let us further assume that force is applied to the button 14 for the purpose of turning the lever 8 counter clockwise. The link 41 will move upwardly until the clamp 48 strikes the end of the lever 39 and the latter will becarrie d upwardly moving the pawl 40 from one tooth to the other." As the tween casings and 28.

lever 8 is rotated the springs 15 and 24 will be put under tension. As soon as the operator releases the button 14, springs 15 and 24 and the weight 23 will start rotating the lever 8 m the opposite direction. The lever will move clockwise until the pin 47 engages the end of the slot in member when further movement will be prevented until the wax 29 has become sufficiently soft to permit the shaft 35 to be rotated. \Vhen the engine starts running part of the exhaust gases will flow through the pipe 30 and the space be- This will cause the wax to soften. As the wax softens the shaft 35 will be rotated slowly by the action of the springs 15 and 24 assisted bythe weight 23. After the shaft has rotated 11 certain amount, the spring 24 will cease to function leaving the weight 23 and the spring 15 to effect further movement. After the shaft has rotated some more the spring 15 will cease to functionafter which the weight 23 will furnish the only force tending to rotate the shaft 35. The weight .23 is not very massive and therefore exerts merely a gentle force, which varies with the intensity of the vibrations to which it is subjected. When the engine gets properly warmed up, the fusible compound will become practically liquid and will offer very little resist ance with the result that the weight 23 will then succeed in moving the lever to the position in which the shoulder 20 abuts the end of the screw 19. It is obvious that an engine warms up more slowly in winter or on cold days, than in summer when the ,weather is warm. My controller should,

connect the interior of the casing with the exhaust manifold by means of a pipe 30 of considerable length. \Vhen the temperature of the circumambient air is low, as in winter, the gases will be considerably cooled before. they reach the casing 26 and they will therefore act slower. .In summer when the air is warm the gases will reach the casing 26 ata higher temperature and will therefore melt the wax more quickly. By properly proportioning the length of the tube 30.

or otherwise varying its heat radiating eharv acteristics. it is possble to compensate quite accurately for the temperature conditions of the air. By means of the stop cock 31 the quantity of gas that is diverted for the purpose of melting the wax 29 may be varied and this will, of course, vary the time required to melt the wax. Since the pipe 30 is directly connected tothe exhaustmanifold, the amount of gas that flows through it in a given time will depend upon the pressure within the exhaust manifold which in turn depends upon the speed of the engine. It is therefore evident that the wax will be more quickly melted when the engine runs fast, which is necessary as the engine naturally heats up faster when it is running fast than when it is running slow.

Let us now assume that-the parts are in the position shown in Fig. 1 and that the driver desires to start the engine. He pulls out the choke 14 and steps on the starter button. The metering pin 4 is moved down thereby opening the carburetor wide giving an excessively rich mixture. As soon as the engine starts the button 14 is released. The springs 15 and 24 promptly move the metering pin to the extent permitted by the lost motion connection between the lever 39 and the link ll, any further closing movement is prevented by the action of the lever 39 which cannot rotate in a counter clockwise direction until the shaft 35 can turn and this cannot turn until the wax 29 softens. As soon as the wax begins to soften, the combined action of the springs and the weight 23 will cause the shaft 35 to move slowly, by the time that the spring 21 has completely contracted, the wax will be soft enough to permit the spring 15- to continue the closing movement. The action of the spring 15 will cease. however, before the metering needle has reached its upward limit of movement and it must be moved the remaining distance by the weight 23. \Vhen the parts have been properly proportioned and adjusted, the me vtermg needle will reach its final position at the same time, or shortly after the engine has attained the proper temperature for the best operation.

In Figs. 4 and 5 I have shown how the setting of my controller can be effected by the same operation that starts the engine. In Fig. 4 numeral 49 designates the starter button to which pressure must be applied for starting the engine.

1 have pivoted a pedal 50 to the floor board 51 in such a position that when it is depressed it will engage the button. A bracket 52 is secured to the dash 53 directly above the pedal. The outer end of this bracket has a bearing 54 in which the shaft 55 is journalled. To one end of the shaft 55 I connect a pulley 56 and to the other end I secure a ratchet wheel 57; A flexible member 58 has oneenol secured to the free end of the pedal 50 and aft-er passing one or more times around the pulley 56 to which it is attached at one point, it turns downwardly and is attached to one end of the spring 59.

pedal, the spring 59 moves thefiexible'mem ber in the opposite direction, thereby rotating the ratchet wheel 57 in a counter clockwise direction. An arm 60 is pivotally connected to the shaft 55. This arm carries lift) portioned that its length is one-half of the requisite movement of the wire 12 and the diameter of the pulley 55 is such that it will lie-rotated through an arc of about 210 degrees when the pedal is moved down into contact with the button 49. The pawl 61 'is so related to the ratchet tetth on, wheel 57 that when the latter is rotated clockwise, it will carry the arm in the same direction. \Vhen the latter has been carried slightly more than 180 degrees, the spring (33, which has been tensioned, causes the arm 60 to complete the circle. By this means the wire 12 is subjected to the requisite pull and released whenever the starter is operated. If the engine is cold and the wax still, the metering needle will be retained in position to give a rich mixture until the engine hcats up. If the engine is hot and the wax soft, the metering needle will be returned almost instantly to lean mixture position.

I have shown a weight 23 attached to the right hand end of the lever B and explained its operation or function. It is, of course not essential that this weight should be a separate part as the end of lever 8 mi ht be enlarged so as to give the proper unbalanced effect.

In my device there is a positive force for opening the carburetor. This force may be applied by the drivers hand to the button 14 or by his foot to the pedal 50. After the carburet0r has been opened both of the sprmgs 15 and 24, as well as the weight 23, tends to close the carburetor. As explained above, spring 24 ceases to function before spring 15 and this in turn ceases to function before the carburetor has been returned to the leanest position. The final movement s effected by the weight 23 whose inertia 1s made use of as well as its weight;

If it should happen that on account of traffic, conditions themixture is too lean to permit slow driving, the wire 12 may be given a pull. This will open the carburetor and produce a richer mixture. When the wax is hot the springs 15 and 24 will almost instantly return the metering pin 4 to lean position but since the last art of the movement is effected by the welght .23 the pin will not return entirely to the lean* est position until the engine speeds up.

Although my device is rather difficult to describe its construction is exceedingly simple and can readily be applied to a carburetor mixture, means forexerting a continuous oft-he type shown. lVhen it is adapted to other makes of carburetors proper changes in construction must of course bemade.

Although I have shown and described a mechanism which automatically sets my de: vice when the starter is operated, this is not at all essential as the simple act of pulling the button 14 while the engine is started causes no inconvenience. hen the means employed in Fig. 1 are used, the metering pin can be held in maximum open position until the engine has started and will then be immediately returned to the position most suitable for the running of the engine, whereas, if the means shown in Figs. 4 and 5 is employed the maximum open position cannot be made available, except in combination with Fig. 1.

Having now described my invention what 80 I claim as new is:

1. In a carburetor, having a movable member for varying the richness of the fuel force tending to move the member to lean mixture position, manually operable means for moving the member to rich mixture position, tliermo-responsive means for holding the member against return to lean mixture position while the thermo-responsive device is cold, but permitting it to return to lean mixture position when the thermo-responsive device becomes heated above a predetermined temperature and means permitt ng the manually operable means to return to normal position independent of the position of said holding means.

2. In a carburetor having a movable member for varying the richness of the fuel mixture, means for exerting a continuous force tending to move themember to lean mixture position, manually operable means for moving the member to rich mixture position, thermo -responsive means for holding the member against return to lean mixture position while the thermo-responsive device is cold, but permitting it to return to lean mixture position when the thermo-responsive device becomes heated above a predetermined temperature, means permitting the manually operable means to return to nor- 'mal position independent of the position of said holding means and a lost motion connection between the movable member and the holding means which permits the movable 116 member to move a short distance towards lean mixture when the manually operable means is released after the movable member has been moved to extreme rich mixture position.

In testimony whereof I affix my signature.

HAVARD FARMEB HUDSON. 

